


It's not cheating if it's me

by MamaMiyaMiya (Problemagician)



Series: Let's Do The Time Warp Again AU [1]
Category: Haikyuu!!
Genre: Age Difference, Alternate Universe, Alternate Universe - Age Changes, Alternate Universe - Time Travel, Fluff and Smut, Future!Iwaizumi, M/M, Older Man/Younger Man, Plot What Plot/Porn Without Plot, Time Travel
Language: English
Status: Completed
Published: 2020-08-06
Updated: 2020-08-06
Packaged: 2021-03-05 23:21:54
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 3,194
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25743514
Author URL: https://archiveofourown.org/users/Problemagician/pseuds/MamaMiyaMiya
Summary: Something something time-space continuum fucked up and now high school Oikawa meets athletic trainer Iwaizumi, married to a future version of himself. Oikawa's a desperate virgin and Iwaizumi always wondered what it'd be like if he had only confessed years ago.“I’ve always wanted to be with you like this.”Iwaizumi must be dreaming, because having him here is already surreal, but now Oikawa has said the exact same thing that made him lose it the first time.“Fuck.”
Relationships: Iwaizumi Hajime/Oikawa Tooru
Series: Let's Do The Time Warp Again AU [1]
Series URL: https://archiveofourown.org/series/1887070
Comments: 35
Kudos: 319
Collections: Beautiful smut (by SKrauch)





	It's not cheating if it's me

“It’s not cheating if it’s me, right?”

“I can’t.”

Iwaizumi faces two options: Fuck this younger version of Oikawa, the one he’d pined over for all of his adolescence, or reject him and break his heart, but protect his dignity.

“You shouldn’t even be here,” he argues, worrying his lip and trying not to get an erection, even though Oikawa is halfway into his lap on the bed, with wide eyes and rosy cheeks. Iwaizumi ignores his blinking phone on the dresser next to him.

This person looks younger than his husband, but he can’t place why. There’s a youthful innocence to his face, one that he never saw when he was younger. He’s not as muscular, but he’s still put in all the work.

 _Would_ it be cheating, if it’s still him? When he goes back to his own time, will future Oikawa remember whatever happens here tonight? Or is it an entirely alternate reality with consequences he’ll never know about?

“Iwa-chan,” he murmurs, on the verge of tears, scooting further so he’s straddling him. “Please. It’s not fair. You remember what you were like in high school, right?”

He exhales. “Yeah.”

Abrasive, mean, practiced romantic disinterest and an oblivious Oikawa who had no idea just how wrapped around his finger he really was.

Still is.

Oikawa takes his hand gently, admiring the wedding band there. “How long until you love me back?”

“I’ve always loved you,” he admits.

Oikawa presses his palms into his eyes, but his shoulders shake and sob for him. “Then why? We could’ve been together so much sooner.”

“I know,” he chokes.

“And now I have to go back to an Iwa-chan who doesn’t admit he loves me, who’s not married to me.”

“I know. I’m sorry, Tooru.”

There’s a minute where no one talks until Oikawa wipes his face and inhales.

“ _Tooru_ ,” he echoes, removing his palms and peering at him with a weary smile. “You say it so nicely.”

Iwaizumi’s fingers find themselves in his hair. “Well, I am eventually married to you. You get used to it.”

“There’s no way future me is used to it,” he whispers.

He chuckles. “Maybe.”

“Iwa-chan,” he says again, that pleading voice of his squeaking, his thighs flexing around his own. “Didn’t you want to be with me when you were younger?”

He doesn’t answer, because the answer is ‘every day.’

“I’m still Tooru. Don’t you want me?”

He doesn’t answer, because the answer is ‘yes.’

Oikawa leans forward, just a breath away. “Just a kiss? I’ve always wanted to kiss you.”

“Just one.”

“Okay,” he says, excited at the innocent prospect.

“Mm.”

Iwaizumi tugs Oikawa’s head forward, gently bringing his lips to his, leaving his fingers in his hair to massage his scalp. Oikawa fills the space like he’s used to, even though everything feels… smaller.

Oikawa still tastes the same as his future self, but the affection this version of him brings feels… bigger.

Needy hands grip his collar and Oikawa deepens the kiss, as if afraid if it ends Iwaizumi really will stop him at one. Even though, right now, Iwaizumi doesn’t want to.

This version of his lover reminds him of their first time together, where they still didn’t have words for what they were feeling so they showed it with their horny bodies and desperate touches. Iwaizumi will never forget it for as long as he lives. He died that day and became who he is now—a man who can’t hide how much he craves Oikawa.

The hand not in his hair grabs at a butt cheek. Iwaizumi shoves him even more flush against his chest, opening his mouth for Oikawa’s hesitant tongue to explore. Not hesitant for long. Oikawa’s hands move to wrap around his neck as he ruts against his chest, starting to moan and whine into him.

God, just like the first night.

“I’ve always wanted to be with you like this.”

Iwaizumi must be dreaming, because having him here is already surreal, but now Oikawa has said the exact same thing that made him lose it the first time.

“Fuck.”

He drags the hand into Oikawa’s pants to cup his bare ass, moaning when he jolts and his hard-on presses into him.

_“Iwa-chan.”_

“Yes. Yes, you’re okay,” he rasps. Iwaizumi pulls away so he can breathe again, eyes looking over the absolutely _orgasmic_ face of Oikawa who’s shivering and lips are covered in spit. He looks like he’ll die without him, and that does wonders for his ego.

It’s nothing like the first night, but maybe it’s better. This version of Oikawa may be an inexperienced, desperate virgin, but Iwaizumi knows his body more than him. More than he’d know for years.

“Please don’t stop kissing me,” he pleads. “Just one more?”

Iwaizumi moves in but changes direction to lick at his neck, sucking on a spot below his ear that this young Oikawa doesn’t know makes him buckle.

“Oh, my _God_. Iwa-chan—that feels…”

“Mhmm,” he murmurs, nursing the spot more and feeling Oikawa tremble.

“I feel weird. I feel like my body is jelly. You’re so good, Iwa-chan. Do you… do you and I have sex often?”

Iwaizumi pulls away from the spot, kissing up to his chin then his lips and smirking against them. “Tons and tons of sex. Sometimes twice a day.”

“I’m so jealous.”

“Don’t be jealous of yourself.”

“But I want to…” Oikawa blushes further. “ _I_ want to have sex with you, too.”

So does he. Maybe he’s sick in the head. “We shouldn’t. You should save that for inexperienced Iwaizumi.”

“Would it even be good?” he protests. “I’m sure you’re a pro. You can show me now and I can show him, right?”

“Nope,” he teases, purposefully flippant.

“Please.” Oikawa ruts against him again. “Something. _Anything_. I’ve always wanted to see your dick hard. I bet your dick is so _big_ , Iwa-chan. I want to see your dick so bad. Can I suck it? Can I at least suck your dick? I want to see you cum. I want to cum with _you_. Iwa-chan, please—”

“You’ve always been so god damn annoying, Tooru.”

“But—”

Both hands slip in his pants to cup both bare cheeks of his ass, helping him rut harder—one clothed hard-on to another. Iwaizumi grunts, moving his own hips as he stares up at Oikawa, who grips his shoulders to hold himself steady.

“Iwa-chan. Iwa-chan, I feel like I’ll cum just like this.”

He laughs at that but stops. “Take it out.”

Oikawa hesitates, blinking down to his pants, but Iwaizumi nods. “Yeah. That. Take it out. Go on.”

He doesn’t hesitate anymore, fumbling cutely with his school uniform pants— _God, that brings back some painfully vivid memories of Iwaizumi fisting himself in Oikawa’s own bathroom, one hand on his dick and the other holding his discarded uniform from the laundry hamper_ —until he awkwardly takes out his hard cock.

It’s perfect. Beautiful. Almost exactly like the one he cherishes now.

Iwaizumi pinches his cheeks. “Touch yourself for me.”

“Ah! You’re not going to touch me?” he frowns.

“Touch.”

Oikawa flinches but shakily does as he’s told, both hands enclosing around his base before gently sliding up and down. Iwaizumi watches it, hungry, mesmerized, the sight of a uniformed Oikawa jerking off scratching a longtime itch he never got to fully realize.

Iwaizumi goes on autopilot. The longer he pedals forward, the easier and easier the long-ago memories and desires come like he’s riding a bike.

“Tell me about school,” he says next, eyes fixed on the leaking tip.

“I-it’s fine… I-I’m doing well, volleyball i-is mostly going well. We’re shooting for, ah, nationals. L-like always…”

“Yeah? And what about me?”

He pokes forward, brushing Oikawa’s fingers when he swirls precum across the leaking tip.

“Mmph, y-you’ve been real mean to me l-lately…”

“Why’s that?”

“I-I kept bragging about… getting a better test score… and so you’re mad a-at me… cause you s-studied so hard at my h-house…”

“Ah… Ya know, I think I remember that.”

Oikawa’s eyes widen and he stills, but Iwaizumi encourages him to continue as he talks. “Yeah… that was only part of the reason.”

“Yeah?”

“That night I hardly studied… got real distracted by your knee brushing mine… and it was so hot you’d removed your shirt…”

He nearly gasps. “You… w-were looking at me?”

“Oh, yeah. All the time, baby. Always thinking of if I was a little braver, how I’d shut you up.”

Oikawa whimpers, mouthing “ _baby_ ” back to him. He’s so goddamn cute.

“How I’d shut you up just like this,” Iwaizumi grunts, leaning back and scooting Oikawa forward to his face. He opens his mouth and sucks at his tip, watching him flinch and whine over top of him.

“Iwa-chan!” he pleads. His hands don’t know what to do with themselves, gripping into his own shirt, tears falling from his eyes as he tries and fails to hold himself together.

“You taste so damn good, Tooru,” he moans over his cock, letting his tongue caress the underside while his lips go further, push him deeper in his mouth.

“Fuck, oh my _God_ , Hajime, you’re so good. You’re _so_ good, ah.”

He pulls off just enough to talk, eyes finding his in the lusty haze. “I know, baby. I know it’s good. Fuck my mouth, Tooru. Grab my hair, I know you want to.”

“I-I can?”

Iwaizumi nods and slaps his ass. Oikawa yelps and buries his fingers in his hair, slowly thrusting and shoving Iwaizumi’s head forward. He gags on his cock just like Oikawa loves and he lets out a silent cry, suddenly coming straight down his throat.

He gulps it all anyway before hurriedly throwing his head back for air.

“Fuck.”

“I am so _so_ sorry, Iwaizumi. I didn’t mean to do that, shit. Are you okay?”

Iwaizumi just laughs and laughs again when he sees the stunned Oikawa’s face. “Tooru, I’m fine… Hey. Hey, I’m fine. I liked it.”

“You… you liked it?” he echoes.

“Yup. Now my turn. Get on your knees, Tooru.”

He hurriedly scurries off his lap, the tip of his half-hard cock still wet with all manner of bodily fluids, and starts moving to the floor before Iwaizumi stops him.

“Nah. Stay here. More comfortable.”

Oikawa watches him work—moving pillows under and behind him, propping himself just enough that he has some height to look down when he removes his pants and underwear, tossing them to the floor. He watches them fall and hesitantly starts removing his shirt before Iwaizumi stops him again.

“No. Leave it on. I need the uniform on.”

And he does, he needs to fuck this version of Oikawa that he never got to. Maybe this was divine intervention. Without thinking, he reaches in the drawer next to him and takes out a bottle of lube.

“O-okay.”

“Come here.”

Iwaizumi spreads his legs, smirking when Oikawa’s eyes widen and sees how big and hard he is. He beckons him over his chest, kissing him with his salty tongue and moving a hand down to his erection. Oikawa slowly jerks him off with one hand, the other flat on his chest.

“I knew you were big,” Oikawa whispers on his lips. “I knew you had a big dick.”

“Just for you, baby. Hey… hey, Tooru?”

“Yes?”

“You ever… played with yourself—with your ass?”

Oikawa pulls away, blushing anew. “U-um. Yes.”

“Yeah? How much? Talk to me. Tell me everything.”

“W-well… At first it was just fingers… it’s not like I could buy a dildo or anything so I-I’d sneak, um, cucumbers with a condom on…”

Iwaizumi laughs at that mental image. “Damn, you were stealing your mom’s cucumbers?”

“S-shut up. She didn’t miss them…”

“Go on, go on.”

“There’s not much else to say,” he rasps.

“No. Tell me more. What were you thinking? How did you fuck yourself?”

Oikawa heaves a heavy sigh, burying his face into his chest. Iwaizumi moves his hand to the lube and flips the cap, squeezing just a little on two fingers before reaching over and sliding the hand into his pants and back over his bare ass. Oikawa squeezes at his chest, arching to give him better access when he massages Oikawa’s delicate hole.

“Fuck,” he squirms.

“Ssh… don’t stop jerking me off, don’t stop talking.”

“I-I always thought of you, of course. I always hoped you were the one fucking me… Or that I was fucking you… Sometimes I hoped you’d catch me… and want to fuck me with the cucumber…”

“Good boy, Tooru,” he grunts, imagining catching his best friend in the act, masturbating to the thought of him, moaning out his name as he opened the door.

“S-so I would just be on my bed, under the covers, never going too deep cause I was afraid I-I’d get stuck… And have to tell my mom I’m gay…”

Iwaizumi gives a breathy chuckle at that, the hand not on his asshole moving to gently smooth his hair. “It’s okay… things will go well.”

Oikawa relaxes at that, humming and then grunting when Iwaizumi sticks a finger inside.

“T-two. Please,” he says, wiggling.

“I dunno,” Iwaizumi teases. “My fingers are bigger than yours, ya know.”

“Iwa-chan, please, two, I can do it.”

“Alright…”

He does as he asks but goes at a leisurely pace, his own high quickly being reached every time Oikawa jerks over him, his fingers fumbling on the sensitive tip of his aching cock. But he won’t come, not yet.

“Fuck, Iwa-chan, you’re so much better…”

“Damn right I am.”

Iwaizumi speeds up, pumping his fingers faster into his asshole, ignoring the twisting in the pit of his stomach that tells him to stop this charade and fuck him into oblivion. When Oikawa moves his hips to fuck himself on his fingers, he starts the third finger.

Oikawa stops, whines, trembles. “O-oh, oh, ah, I don’t know if I can…!”

“C’mon, Tooru, you know you can. Relax. It’ll feel real good soon. You gotta be relaxed if you want me to fuck you, baby.”

“Yes, yes, okay…”

“Look here. Kiss me.”

Oikawa nods and moves his face off his shoulder to face him. Iwaizumi freezes when he sees his expression, glazed and nearly drooling. It’s a face he’d dreamed about for years, and it’s right in front of him.

“Jesus.”

“Iwa-chan?”

“God, you’re perfect. You’re so good for me.”

He growls and shoves his lips against his, bruising when he kisses him and hungry when his tongue thrusts itself down his throat.

The third finger successfully squeezes itself inside, pumping at a peace he knows isn’t gentle but he needs Oikawa ready and he needs him ready yesterday.

“Okay. Okay, Tooru, I need—”

“Iwa-chan, yeah, I can do it. I can do it.”

“Let me know if it hurts.”

“Okay.”

Iwaizumi nips at his lips. “Promise me you will. You have to promise.”

“I promise,” Oikawa nods, a small smile on his face.

“Good.”

He manhandles him, shoving him to his back and dragging those damned uniform pants off his legs. Oikawa helps with his underwear next, and Iwaizumi throws both legs over his large shoulders. It’s in this position, one he knows so well, that he really can tell this isn’t his husband. Oikawa usually takes effort, too heavy to heave his legs with the ease he just has. And this Oikawa looks so much smaller than he’s used to, the smirk replaced with nerves and desperation.

It’s so fucked up, it’s so wrong, but Iwaizumi feels like he’s back in high school, about to make love to the boy he’s loved his entire life for the very first fucking time.

He’s probably about to ruin him for his inexperienced self, but God, he’s too selfish to give a fuck about a version of himself that’s not right here.

_Sorry, I’m an asshole, but you already knew that._

“Relax, keep your eyes on me,” he reassures. Iwaizumi dribbles more lube over himself and Oikawa’s asshole. Oikawa’s virgin asshole.

“Okay,” he swears, hands clenching and unclenching in the sheets.

“What do you need, baby?”

“You, Iwa-chan. I need your cock so badly.”

“Damn right you do.”

He slowly eases the tip in, lets Oikawa adjust and doesn’t let his over eagerness affect him. Iwaizumi grips him in place hard, smiling as his shallow thrusts go in, out, in, out, in, out.

“Hajimeeee,” he whines. “Fuck me, please. Please fuck me, please more, please more, deeper—”

“Jesus Tooru,” Iwaizumi half-laughs, half-wheezes. “You keep talking like that and you’re going to regret it.”

“I won’t,” he protests. “I won’t. Give it to me. Please, I can take it. Please fuck me, _fuck me already_!”

“Fucking hell,” he growls.

Iwaizumi _does_ fuck him—he’s unable to resist Oikawa no matter which version of him it is. He grinds into him, leaning down over him to drive himself deeper, watching Oikawa’s face contort and his eyes roll back.

“Oh my God. Yes—yes—you’re so good. Hajime! Hajime, fuck! _Fuck,_ oh man. I love your cock. I love your cock _so much_ , Iwa-chan. I’m gonna come, I’m gonna come again. I’m gonna die, Iwa-chan.”

He wails and Iwaizumi lets it go straight to his cock. “You’re so _fucking_ tight, Tooru. You gonna cum from just your ass getting fucked, baby?”

“Yes, yes, I ammmm, it feels too good!”

Iwaizumi laughs, slowing down just enough to kiss his lips before continuing his speedy thrusts.

“Fuck, baby, is this a good first time?”

“Yes, _yes_ , Iwa-chaan…”

He bites Oikawa’s neck, flicking his tongue over the spot he knows will make him cum. He does, hard, jerking and clenching over his cock. But Iwaizumi doesn’t stop, lets himself slow for Oikawa to calm down before fucking into him at the pace he loves the most. Deep, deep, shallow, deep.

“Come on Oikawa, I’m not done with you. Open those pretty eyes of yours and watch me fucking you.”

Oikawa does, rasping for air, eyes teary and beautiful when they land on his face and then trail down to the cock still inside him.

“Iwa-chan…”

“Yeah, baby. I’ve always wanted to fuck you just like this, Tooru. Don’t forget that. Don’t forget how good I made you feel tonight, how I made you cum twice like a little doll. I love you, Tooru.”

“I love you, too.”

Iwaizumi finally comes, shoving himself deep in Oikawa’s tight little ass just like he used to fantasize. Oikawa’s mouth opens and little breathy mewls come out.

“Fuck…”

Oikawa says nothing, eyes finally closing and head rolling to the side. Damn. He may have just fucked him unconscious, not that he’s complaining. Iwaizumi gently pulls out and stares at the mess all around him.

It’s not cheating if it’s still Oikawa, right?

He bites his lip and reaches for his phone, reluctantly opening the recent messages from his husband.

Iwaizumi’s fear turns to laughter.

“I-Iwa-chan?” Oikawa sturs.

“Sorry. Uh, it’s just… young me is here, too. With the older you.”

“Really…? Are they talking?”

“Something like that.”

It’s not cheating if his husband’s done the same damn thing.

**Author's Note:**

> Future!Oikawa: Younger you literally begged for it.  
> Future!Iwaizumi: Younger you literally cried for it.  
> Oikawa: .
> 
> **Update: Yes, there will be a sequel with Older!Oikawa and Younger!Iwaizumi haha no need to ask anymore LOL. The enthusiasm has been lovingly noted thank you!**


End file.
